.Key Technologies will develop a portable, rugged device that wili determine hematocrit of a blood sample accurately and rapidly. The device will be handheld and will require a small blood draw of less than 10 cc. No special sample preparation will be required. The test results will be available in less than one minute, and will be accurate to within 2 percent of the values determined by a laboratory cell counter. Phase I of the hematocrit meter project conclusively demonstrated that the proposed techniques can be used to measure hematocrit precisely. During Phase II, the product development phase, Key Technologies will work with the ultimate users to develop a handheld prototype device. Correlations developed in Phase I will be verified using the new configuration. Testing will include freshly drawn blood samples, and a broad base of patients and pathologies. Key Technologies will determine and report the accuracy and precision of the system. PROPOSED COMMERCIAL APPLICATION: Hematocrit is widely used by medical personnel for diagnostic and monitoring purposes. Existing devices that measure hematocrit are costly, immobile, and slow, or inaccurate. The UltraCrit will be accurate, portable, and affordable, giving it a significant advantage over the existing technologies and allowing it to penetrate new markets.